Fuels containing a deposit-control additive



. lines which burn cleanly,

United States Patent- FUELS CONTAINING A'DEPOSIT-CONTROL ADDITIV ERobert Y. Heisler and Stanley R.

Norman Alpert, Pougbkeepsie, Texas Company, Delaware No Drawing.Application December 23, 1955 Serial No. 554,925

13 Claims. (Cl. 44-70) Newman, Fishkill, and

tained by the addition of a minor amount of a polyglycol carbonate esterof prescribed composition.

As automobile manufacturers annually raise the compression ratioof theirautomobile engines in therace for' higher horsepower, the need becomes:greaterforgasothat is, have lowv deposit-forming tendencies. Enginedeposits-which findtheir. origin in the fuel are primarily responsiblefor surface ignition phenomena such as preignition. and "octanerequirement increase (ORI) which is the tendency of spark ignitionengines inIservice to require higher octane fuels *for'properperformance. As a consequence, gasoline manufacturers have'placedincreasing stress on reducing the :depositforming tendencies of their.fuels andhave resorted to various additives either to reduce theamountofdeposits or to minimize their effects. The present invention involvesthe discovery that a particular class of polyglycol derivatives areoutstanding in controlling the depositforming tendencies of hydrocarbonfuels.

The improved hydrocarbon fuels-of this invention'contain a polyglycolcarbonate ester of the general formula ROOCO (R0 COOR" wherein R is adivalent aliphatic radical containing-at least 2 carbon atoms, R and Rare aliphatichydrocarbon radicals containing between 3 and 18 carbonatoms and n is an integer having a value of at least 2, in an amountsufiicient to reduce the deposit-forming tendencies of the fuels. Thepolyglycol carbonateester is effective in the motor fuel inconcentrations as low as 0.01 volume percent but concentrations of 0.04to 0.3 volume percent are normally employed. There is no critical upperlimit of concentration, but economic considerations'dictate thatconcentrations less than 1.0 volume percent polyglycol carbonate bepresent in the fuel.

The polycarbonate esters which inhibit the depositforming tendencies ofhydrocarbon fuels arereadily formed by a series of reactions involvingthe formation of an alcohol chloroformate by reaction of phosgene withan alcohol and subsequently reacting the alcohol chloroformate with apolyglycol in thepresence of a hydrogen chloride acceptor, such aspyridine or quinoline. An alternate reaction procedure involvesformation of a polyglycol dichloroformate by reaction of polyglycol withphosgene and subsequent reaction of polyglycol dichloroformate with analiphatic alcohol in the presence of .a hydrogen chloride acceptor. Thepreparation of compounds of this type is disclosed in U. S. Patents2,370,567 and 2,370,569.

The hydrocarbon fuels of this invention are characterized by lowdeposit-forming tendencies with theresult that an engine operatedtherewith shows exceptionally clean intake system, combustion space,valves, ring belt' area and injection system if a diesel engine; Thelowdeposit level in the engine minimizes surface ignition in allits.manifestations,.mainlypreignition and knock. In

N. Y., assignors to The New York, N. Y., a corporation of wherein R'is adivalent aliphatic radicalcontaining at TABLE I Approximate Molecu-Weight Boiling lar Wt. C to 0 Point, Ratio Ethylene glycol bis (allylcarbonate) 560 230 2. O0 Diethylene glycol bis (allyl carbonate). 660274 1. 57 Diethyleneglycolbis(n-amylcarbonase). 720 334 1. 71 Diethyleneglycol his (methyl atnyl carbonate) I 700 362 1.93 Tetraethylene glycolbis (allyl carbonate 790 362 1.33 Tetraethylene glycol bis (2-ethylhexylcarbonate 506 2. 18 Tetraethylene glycol bis(amyl' carbonate 795 422 1:67 Polyglycol (av. mol Wt. 300) bis(2-ethylhexyl carbonate) 644 2.05Polyglycol (av. mol wt. 400) bis (Z-ethylhexyl carbonate) 744 1.Diethylene glycol bis(n-buty1;carb0n-' ate) 670 306 1. 50-

2,844,448 Patented July 22, 1958 addition, the low deposit level reducesthe engines octane requirement increase. In addition, deposits onsurfaces contacted'by the lubricating oil, such as piston skirts andcylinder walls, are very markedly reduced.

Polyglycol carbonate esters usable in the process of the invention areexemplified by the following: diethylene glycol bis(allyl carbonate),triethylene glycol bis(allyl carbonate), tetraethylene glycol bis(allylcarbonate), diethylene glycol bis(n-amyl carbonate), triethylene glycolbis(n-amyl carbonate), tetraethylene glycol bis(namyl carbonate),dipropylene glycol bis(n-amyl carbonate), polyglycol (av. mol wt. 300)bis(n-amyl carbonate), polyglycol (av. mol wt. 400)bis(Z-ethylhexyl.carbon-. ate), tetraethylene glycol bis(2'-ethylhexylcarbonate), diethylene glycol bis(2-ethylbutyl' carbonate), diethyleneglycol"bis(n-propyl carbonate), polyglycol (av. mol. wt.

400) bis(n-amyl carbonate), diethylene glycol bis(4- pentenylcarbonate), tripropylene glycol bis(2-ethylhexyl carbonate), diethyleneglycol bis(isoamyl. carbonate),v

R'OOCO (RO),,COOR

least 2 carbonatoms, R and R" are aliphatic hydrocarbon radicalscontaining at least 3 carbon atoms and: n isan integerhaving a value ofat least2, are ineffective as deposit-control additives in hydrocarbonfuels. example, a monoglycol carbonate ester such as ethylene glycolbis(allyl carbonate) is ineffective while diethylene glycol carbonateesters such as diethylene glycol bis(allyl carbonate) are excellentdeposit-control additives. Similarly, diethylene glycol-bis(ethy1carbonate) is ineffec-- tive in controlling deposits while diethyleneglycol bis (allyl carbonate), is a very good deposit-control additive.-As a result of intensive experimentation, the following generalizationshave been made with regard to the properties required for a glycolcarbonate ester to exhibit deposit-control properties.

The polyglycol carbonate esters that are effective in' reducing thedeposit formation in hydrocarbon fuels are all characterized by boilingpoints above 650 F.', a. molecular weight above 270 and a carbon-tooxygen ratio by weight below 2.50. Apparently, the polyglycol carebonate ester must possess all of these properties simultaneously inorder to impart deposit-control properties to hydrocarbon fuels. InTable'I below the boiling point,

molecular weight, and C to 0 ratio by weight for eifec tive andinelfective glycol carbonate esters are shown.

- Not distilled- -too high boiling.

For

In summary, the following conclusions can be made as to the requirementsof each section of the additive molecule for the production of a glycolcarbonate ester having deposit-control properties. The alkylene oxideunit, that is the (RO),, group, must contain at least 2 units; as manyas 2 to repeating units can be used in this portion of the molecule;ethylene oxide and propylene oxide derivatives are preferred from thestandpoint of cost, availability and effectiveness. Two carbonateradicals are required since polyglycol mono carbonate ester compoundsare ineffective as deposit-control additives. The terminal aliphaticradicals must contain at least three carbon atoms; aliphatic radicalscontaining 3 to 10 carbon atoms are preferred. In both the alkyleneoxide group and in the terminal aliphatic radicals, straight chainradicals are preferred to the branched chain hydrocarbon radicalsalthough if the overall molecule is large, moderate branching can betolerated. Similarly, primary alkyl carbonate esters are preferred tosecondary and tertiary carbonate esters.

As a general rule, longer chain terminal radicals are combined withpolyglycols containing a larger number of repeating alkylene oxide unitswhile lower molecular weight terminal aliphatic radicals are combinedwith polyglycols containing a small number of repeating alkylene oxideunits. Thus, a 2-ethylhexyl terminal radical is preferably used in theformulation of a tetraethylene glycol carbonate ester than in theformulation of a diethylene glycol carbonate ester. Formulating thepolyglycol carbonate esters following this general rule assures that theresulting additive has a carbon to oxygen weight ratio less than 2.5.

The polyglycol carbonate 'ester is effective as a depositcontroladditive in concentrations between 0.01 and 1.0 volume percent of thefuel. Generally, dirtier fuels having a higher concentration of olefiniccomponents require higher concentrations of the polyglycol carbonateester whereas cleaner burning premium fuels are improved with respect todesposit-forming characteristics by smaller concentrations of thepolyglycol carbonate ester. In general, dirtier gasolines require apolyglycol carbonate ester concentration between 011 and 0.3 volumepercent whereas clean-burning premium fuels only need a polyglycolcarbonate ester concentration of between 0.01 and 0.08 volume percent.As indicated previously, there is no critical upper limit from afunctional viewpoint but economics dictate that the polyglycol carbonateester concentration be less than 1 volume percent.

The polyglycol carbonate esters of the type described in this inventionare effective in controlling deposits in hydrocarbon fuels havingboiling points up to about 700 F., although benefits also result whenthe polyglycol carbonate esters are added to fuels containing residualstocks of higher boiling point. The major application of the additive isin gasoline for automotive engines wherein fuel-derived engine depositshave become a particularly vexing problem. The deposit-formingproperties of diesel fuels and fuels designed for use in jets and gasturbines are also improved by the polyglycol carbonate esters of thisinvention. In diesel fuels the presence of the polyglycol carbonateester maintains the injection system and combustion zone in a cleancondition. This is particularly important with the increasing use of theso-called economy diesel fuels, that is fuels having a high sulfurcontent or containing cracked or residual stocks. P olyglycol carbonateesters find particular applicationin jet fuels which are used as coolingmediums prior to their consumption. A polyglycol carbonate estercontaining jet fuel is an excellent heat exchange medium sinceit isrelat-ively free from deposits in the cooling system and burner nozzlewhere deposits cannot be tolerated.

The deposit-forming properties of both regular and premium gasolines,both of the leaded and of the nonleaded type, are improved by theaddition of polyglycol carbonate esters. The gasolines to which thepolyglycol carbonate esters are added can be broadly defined as ahydrocarbon fuel having a boiling point up to approximately 400 F.

The action of polyglycol carbonate esters of the prescribed compositionin controlling the deposit-forming tendencies of motor fuel wasdemonstrated by a Modified Chevrolet Deposits Test-CRC FL-2-650. Thelaboratory engines are operated under the standard conditions of thistest with the except-ion that crankcase oil temperatures were 10 F.lower, the water jacket temperatures were 5 F. lower, and the crankcasesof the test engines were ventilated. These modifications are in everycase in the direction of making the test more severe and are intended tosimulate low temperature conditions wherein deposit formation is mostpronounced. After the termination of each run, the engine isdisassembled and its parts are evaluated by a merit system adapted fromthe CRCL-41252 Test. This merit system involves visual examination ofthe engine part in question and their rating according to deposits bycomparison with standards which have assigned ratings. For example, arating of 10 on piston skirt designates a perfectly clean piston while arating of zero represents the worst condition. Similarly, a rating of ontotal engine deposits represents a perfectly clean engine, etc.

In Table II there is shown the decrease in deposit formation resultingfrom the addition of various polyglycol carbonate esters to a highquality regular grade gasoline comprising a mixture of thermal crackedstock, fluid catalytically cracked stock and straight run gasoline. Thisregular base fuel had an 87.0 ASTM Research octane rating, contained2.90 ml. of TEL per gallon, had an API gravity of 58.0 and a boilingrange between 106 F. and 936 F.; the. base fuel was negative in thecopper corrosion test and had an oxidation stability in the ASTM test of530 minutes minimum. The reference fuel also contained minor amounts ofgasoline inhibitors, namely N ,N-disecon-dary butyl-p-phenylenediamine,lecithin, and N,N-disalicylidene-l,2-diarninopropane. In all the runs inTable II, the laboratory engines in the Chevrolet S-II test werelubricated with Advanced Custom Made Havoline, a heavy duty type oilmeeting Supplement I require- \ments and manufactured 'by The TexasCompany.

In Table II the concentration of additives in the base fuel was 011volume percent in each instance.

TABLE II Piston Total en- Skirt gine deposits Base fuel 4. 7 77. 7 Basefuel plus the following:

Ethylene glycol bis(allyl carbonate) 3. 5 70. 5 Diethylene glycolbis(allyl carbonate) 8. 5 84. 5 Triethylene glycol bis (allyl carbonate)8. 7 86. 7 Tetraethylene glycol bis(allyl carbonate) 9. 2 89.2Diethylene glycol bis(amyl carbonate) 8. 8 87. 8 Tetraethylene glycolbis(amyl carbonate) 7. 5 82. 5 Diethylene glycol bis(n-butyl carbonate)8. 5 87. 5 Diethylene glycol bis(2-ethylhexyl carbonate). 5.8 80. 8Polyglycol (av. mol wt. 300) bis(Z-ethylhexyl carbonate) 9. 3 91. 3Tetraethylene glycol bis(2-ethylhexyl carbonate 6. 8 84. 0 Triethyleneglycol bis(allyl carbonate). 8. 7 86. 7 Triethylene glycol bis (amylcarbonate) 9. 0 91.0 Polyglycol (av. mol wt. 400) bis(2-ethylhexylcarbonate) 8. 7 87. 7 Polyglycol (av. mol wt. 300) bis(amyl carbonat 9.5 89. 5 Polyglycol (av. mol wt. 400) bis(amylcarbonate) 9. 2 87. 2

The data in the above table clearly show that a polyglycol carbonateester of the prescribed formula is necessary in order to producea motorfuel of decreased depositforming tendencies. Ethylene glycol bis(allylcarbonate) gave a dirtier piston skirt and a dirtier total engine ratingthan the base fuelwhereasdiethylene glycol bis(allyl car- 'bonate)substantially improved boththe piston skirt and totalengine rate. ,Itisfalso significant that higher molecular weight alkyl radicals in thecarbonate ester are "advantageously com- 6 of N,N'-disecondarybutyhp-phenylenediamine, a gum inhibitor, per thousand barrels ofgasoline, about 1.2 pounds of N,N'-disalicylidene-1,Z-diaminopropane, ametal deactivator, per thousand barrels of gasoline, and

bined with polyglycols of a large number of alkylene 5 about 1.1 poundsof lecithin, a tetraethyl lead stabilizer, oxide units than with lowermolecular weight polyglycols. per thousand barrels of gasoline. Thisresult is'evident'from' a'comparison of the ratings TABLE Iv obtainedwith diethyleneglycol bis(2-ethylhexyl carboni t d tetraethyleneglycolfljis(z ethy]hexyl carbonate) Engine cleanliness m modifiedChevrolet S-II test and polyglycol (av. molweight 300) bis(2-ethylhexylcarbonate). f Piston Total The data in Table II shows that regulargasoline fuels 8km 521515.; containing 0.1 volume percent polyglycolcarbonate of prescribed composition are approximately equivalent to Basemp1 7,5 55,2 premium grade 'gasolines with regard to deposit-forming glfl gg g g e p c t et ylene g y 8 0 87 o tendencies; The piston skirtratings of 8.0 to 9.5 and Base {119L010 g-55.1.1 55.iigggeiggg'gieggi'the total engine ratings of 84 to 91+ are better ratlngsb1S(a11Y1carbnat) 857 than are obtained with some premium fuels. Theability I f p yg y carbonates to boost regular grade f s t Thespecificity of the polyglycol carbonate ester structhe enginecleanliness level of Premium grade fuels is a Q. tures is furthershown'by a consideration of the informaignlficant advance and a ub ant astep forward to 801V- tion recorded in Table V. Numerous compounds were111g The s uffa'ce ignition P ms encountered in g I evaluated thatcontained portions of the preferred overall compression engines.structure, but in no case was an outstanding deposit con The effect ofvarying concentrations of diethylene glytrol additive obtained. In somecases, the additive decol 'bis(allyl carbonate) in regular fuel areshown in graded the base fuel. Evaluation of the additives was Table Thedata in Table III indicate that a conmade in the high quality regulargrade gasoline previously centration between 0.1 and 0.2 volume percentis necesdescribed. j

TABLE V Concen- Molec- Weight Piston Total Additive tration, uiar C to OSkirt Engine Volume Weight Ratio Rating Rating Percent N I 4.7 71.7Diallyl 0. 05 9s 4. 5 5. 0 75. 0 130-- 0. 10 5. a s2. 3 Diallyl ether 0!diethylene glycol. 0. 10 186 2. 5 3. 7 74. 7 Dibutyletheroftetraethylene glycoL 0.20 306' 2.4 5.0 76.0 Diethyl ether ofdiethylene glycol- 0. 20. 162 2. 0 5.0 71. 0 Allyl alcohol o. 05 7o 2.25 4. 2 72. 2 Diallyl. carbonate 0. 10 142 1. 75 4. 8 75. 8Di-Z-ethylhexyl carbonate 0. 10 296 4. 25 5. 7 81. 7

sary in order to obtain optimum results with diethylene glycol bis(allyl carbonate) in regular grade gasoline.

In Table IV the action of a polyglycol carbonate ester in reducing thedeposit-forming properties of a premium grade fuel are shown. Since thepremium grade fuel already has an excellent rating with respect to thetendency'to form'deposits, theaction of a polyglycol carbonate ester isnot as striking jasin the regular grade fuel. However, significantimprovement in the deposit-forming tendency in the premium grade fuel iseifected by the addition of the polyglycol' carbonate ester and smallerquantities of an additive are needed in order to obtain optimum resultsof the premium grade fuel.

'The'reference fuel employed'in Table IV was a" high quality premiumgrade fuel'comprising mainly. fluid catalytically cracked stock andstraight run gasoline. The reference fuel had a 95 A. S. T. M. researchoctane rating, contained 2.74 ml. of TEL fluid per gallon, had an APIgravity of 6 0 to 65 and a boiling point range between 100 and 398 F.;the base-fuel was negative in the copper corrosion test and hadanoxidation stability in the ASTM test of 240 minutes minimum. Thereference fuel also contained minor amounts of conventional gasolineinhibitors, for example, approximately 6 poundsw Octane requirementincrease.0ctane requirement in- A 45 crease of engines in service is'anold problem that becomes more severe with the modern high compressionengines. An engine which has an initial octane requirements, of'85 oftenwill develop a-need for a octane fuel during service. Ithas beenpostulated that octane requirement increase is attributable partially toengine design and partially to the fuel and lubricant.

Reduced octane requirement increase was demonstrated in-the laboratoryfor the additive-containing motor fuel of this invention in comparisonwith the reference fuel by the following procedure:

LAUSON H-Z ORI TEST PROCEDURE TABLE VI Variable Condition Test, Hours Toequilibrium 0. R.=200 hr. Wattmeter Reading 1,5001,600.

Fuel Flow, lbs. per hr 1.6 :t; .04. Coolant Temp., "F 210 :1; 5. d: 5.

011 Temp., F-

e1 Check once each day.

0 Inches (each hour).

Record each hour.

Orifice Press. Drop "Octane requirement of. the engine was determinedapproximately every 24 hours. Before taking octane requirementthe oillevel waszchecked and necessary addi- 1 r r tions made and the following'items determined and recorded.

Compression pressure at operating throttle position Air temperature, F.

Barometer reading, in. Hg

Spark advance, B. T. D. C. (should be degrees) Amount of oil addedEquilibrium octane requirement was reached when the engine had operatedfor 50 hours with a change in ORI of 2 numbers or less.

A modified Model H2 Lauson engine, which is a single cylinder, liquidcooled, four stroke spark ignition engine with a bore of 2% inches and astroke of 2% inches giving a displacement of 14.89 cubic inches, wasused. Power output was rated at 4.3 H. P. at 2400 R. P. M. Compressionratio of the engine was 6.5 :1

using a modified head. The original flywheel magneto was replaced with aBendiX-Scintella magneto, Type.

GER-4R and coupledto the forward end of the engine crankshaft to provideignition. The engine was operated under the following conditions:

Engine speed 1800 R. P. M.

Engine load 1600 Watts.

Spark advance 20 B. T. C.

Fuel flow rate l.6#/hr.

Air-fuel ratio 13.5 :1

Coolant temperature 210 F.

Carburetor air temp 100 F. v Oil temperature- 175 F.

Test duration App. 200 hr. to equilibrium octane requirement.

The octane requirement of the engine was determined with primaryreference fuels on the clean engine and?" after each period of operationuntil equilibrium octane The loss in weight of the two compression ringsis taken as a measure of the low temperature wear properties of the fueland oil combination. By holding the 'oil constant, the relative wearcharacteristics of fuels can be determined. Using Advanced Custom MadeHavoline oil, previously described, the results shown in Table VI],below, were obtained with a premium fuel with and without a polglycolcarbonate ester:

TABLE VII Low temperature wear Mg. Weight Fuel Loss of Compression RingsPremium fuel 50 Premium fuel plus 0.2% by volume diethylene glycol bis(allyl carbonate) 42 The test used for high temperature wear andcorrosion is an extended version of the CRCL41252 Test. In the extendedtest, the total test time is 72 hours inljstead of the usual 36. Thisincrease in test time makes the test more severe.

Bearing weight loss is the criterion for possible corrosive or wearaction. Asindicated in requirement was attained. The differencebetweenthe initial (clean) octane requirement and the equilibrium octanerequirement is known as the octane requirement increase or ORI.

The premium grade fuel employed in Table IV gave an octane requirementincrease of 20 units in the above test whereas the same fuel plus 0.2volume percent diethylene glycol bis(allyl carbonate) showed a maximumincrease of 17 units in this test. Of more significance is the fact thatthe octane requirement increase would successively build up to a maximumof about 17 using the additivecontaining fuel and then would quicklydrop to an increase of 7 units followed by successive buildups and dropsof a similar magnitude. It has been theorized that these periodic dropsin octane requirement increase in the engine are a consequence of largeareas of deposits being rapidly removed by the action of the polyglycolcarbonate esters during engine operation.

Effect of additives on engine wear. Frequently, in the course ofdevelopmentof useful additives for improved fuels, deleterious effectswill be encountered. The deleterious effects may greatly overshadowpossible benefits. Deleterious action is frequently associated withincrease in engine wear of such engine parts as piston rings, cyl

inder walls, bearings, and valves. The fuels obtained by the addition ofa minor amount of a polyglycol carbonate ester of prescribed compositionare unusual in that no deleterious effects have been encountered in thelarge amount of engine testing conducted. In fact, with respect to wearof vital engine parts, it has been found that wear is actually decreasedunder both low and high temperature conditions.

The test used for low temperature wear evaluations uses a 1949 Pontiac 8piston and Sealed Power IB-10 compression piston rings installed in aCFR high-speed crankcase. operating conditions are as follows:

The cylinder liner is nitridedcast'iron. The

Table VIII, below, no deleterious eifect was noted for a polyglycolcarbonate ester.

TABLE VIII High temperature wear CRC-L-4 extended test Gram Weight; FuelLoss of Bearing Regular Grade Fuel 0.079 Regular G rade Fuel plus 0.2%by volume diethylene glycol b1s(a11y1 carbonate) 0. 044

The foregoing data prove that the polyglycol carbonate esters ofprescribed composition are outstanding. fuel additives for controllingdeposits and at the same time do not possess any deleterious effectswith regard to engine wear.

Obviously, many modifications and variations ofthe invention, ashereinbefore set forth, may be made Without departing from the spiritand scope thereof, and, therefore, only such limitations should beimposed as are indicated in the appended claims.

We claim:

l. A normally liquid hy rocarbon fuel for internal combustion enginescontaining a polyglycol carbonate ester having a carbonto oxygen'weightratio below 2.5

and a boiling point above 650 F. and the following general formula ROOCO(R0) COOR" wherein Ris a divalent aliphatic hydrocarbon radicalcontaining at least 2 carbon. atoms, R and R-' are aliphatic hydrocarbonradicals containing between 3 and 18' carbon atoms and n is an' integerhaving a value of 2 to 10, said glycol carbonate ester. being present inan amount suflicient to reduce the deposit-forming property of saidfuel.

2. A hydrocarbon fuel according to claim 1 containing 0.01 to 1.0 volumepercent of polyglycol carbonate ester.

3. A hydrocarbon fuel according to claim 1 containing 0.04 to 0.3 volumepercent of a polyglycol carbonate ester.

4. A hydrocarbon fuel according to claim 1 in which said R and R contain3 to 10 carbon atoms.

5. A gasoline containing a polyglycol carbonate ester having a carbon tooxygen weight ratio below 2.5 and a boiling point above 650 F. and thefollowing general formula ROOCO(RO),,COOR" wherein R is a divalentaliphatic hydrocarbon radical containing at least 2 carbon atoms, R andR" are aliphatichydrocarbon radicals containing between 3 and 18 carbonatoms and n is an integer having a value of 2 to 10, said glycolcarbonate ester being present in an amount suflicient to reduce thedeposit-forming property of said fuel.

6. A gasoline according to claim 5 containing 0.01 to 1.0 volume percentof polyglycol carbonate ester.

7. A gasoline according to claim 5 containing 0.04 to 0.3 volume percentof a polyglycol carbonate ester.

8. A gasoline according to claim 5 in which said R and R" contain 3 to10 carbon atoms.

9. A gasoline containing 0.1 to 1.0 volume percent diethylene glycol bis(allyl carbonate).

10. A gasoline containing 0.1 to 1.0 volume percent diethylene glycolbis(amyl carbonate).

11. A gasoline containing 0.1 to 1.0 volume percent tetraethylene glycolbis(allyl carbonate).

12. A gasoline containing 0.1 to 1.0 volume percent polyglycol (av.molecular weight 300) bis(2-ethylhexy1 carbonate).

13. A gasoline containing 0.1 to 1.0 volume percent triethylene glycolbis (allyl carbonate).

References Cited in the file of this patent UNITED STATES PATENTS2,331,386 Gaylor Oct. 12, 1943 2,379,252 Muskat et al. June 26, 19452,651,657 Mikeska et al Sept. 8, 1953 2,789,891 Brandes et a1 Apr. 23,1957 UNITED STATES PATENT OFFICE CERTIFICATE OF CORBECTIQN Patent No.2,844,448 1958 Robert. L Heisler at El It is herebyl certif-ied thaterror appears in the printed epeoification of the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 2, line 62, Table I, first column thereof, thirtl item, for"bis(n amyl carbonase)" read ==bisxfin amyl carbonate); oollmm 4,, line34, for "936 F," read 396 Fo columns 5 and. 6, Table V first columnthereof, second. item, for "Diallyl" read Dflallyl ethcr -o Signed andsealed this 14th day of October 1958;"

SEAL fittest:

KARL VAQUJINE ROBERT E. WATSON Attesting Officer Commissioner of Patents

1. A NORMALLY LIQUID HYDROCARBON FUEL FOR INTERNAL COMBUSTION ENGINESCONTAINING A POLYGLYCOL CARBONATE ESTER HAVING A CARBON TO OXYGEN WEIGHTRATIO BELOW 2.5 AND A BOILING POINT ABOVE 650*F. AND THE FOLLOWINGGENERAL FORMULA